Sheriff's officials in Northern California are investigating whether a dog's fatal poisoning is linked to research its owner has been conducting, a sheriff's spokesman said on Wednesday.

The 10-year-old Labrador mix named Nyxo died this month in Humboldt County after eating red meat laced with brodifacoum, a rat poison. The dog's owner, ecologist Mourad Gabriel, has been studying brodifacoum's effects on Pacific fishers and northern spotted owls, Gabriel told the Center for Biological Diversity, a Tucson, Ariz.-based animal advocacy and research group.

The center has offered a $2,500 reward for information.

The Humboldt County Sheriff's Office has opened an animal cruelty investigation and is looking into the possibility that Nyxo was targeted because of Gabriel's research, Lt. Wayne Hanson said.

No other neighbors have reported using rat poison or having their animals poisoned, and Gabriel did not let the dog loose in the neighborhood, according to the sheriff's office.

Gabriel is co-founder and executive director of Integral Ecology Research Center, a nonprofit research organization, according to the group's website. He let Nyxo into the backyard of his Blue Lake home on the night of Feb. 2, according to the sheriff's office.

Nyxo came back inside a short time later, but Gabriel woke up the next morning to find the dog had vomited red meat and was having seizures. He had only fed it dry dog food, the sheriff's office said.

He took the dog to an animal hospital in Arcata, but Nyxo died. A necropsy conducted at the University of California, Davis, concluded the dog had been poisoned by brodifacoum.